1. Field of the Invention
This invention relates to devices, such as door closers, wherein a sliding rod is attached to a door or the like to close it or hold it in a desired position.
2. Description of Prior Art
In many door closers of the telescoping spring return type, a braking mechanism is mounted on a central telescoping member or rod to hold a door open. This design operates when the brake, usually a clip or washer located about the rod, is manually positioned to prevent the rod from retracting into a spring-containing housing. A difficulty with this type of closure is that it must be manually set and released, and this is inconvenient if a person's hands are not free, such as when an article is being carried through the doorway.
Devices have been designed to overcome this problem. U.S. Pat. No. 4,920,609 issued on May 1, 1990 to Lin and U.S. Pat. No. 4,357,731 issued on Nov. 9, 1982 to Strauss disclose latching mechanisms to hold a door open, and upon further opening of the door, a release mechanism is employed to allow the door to close. However, the latching mechanisms in these patents are located at a fixed distance along the central rod of these inventions which does not cater for intermediate latching along the rod, thereby not being able to hold doors open at any desired intermediate position.
U.S. Pat. No. 4,639,969 issued Feb. 3, 1987 to Obenshain discloses a door closer mechanism with a pawl and ratchet mechanism to hold a door open at an intermediate position. By pushing the door tending to close it, the ratcheting mechanism is reversed automatically, thereby allowing the door to close. However, a difficulty with this device is that the door can close unexpectedly, such as by a gust of wind or an inadvertent push, and possibly exposing an unwary user to a risk of injury.